1. Field of the Invention
This invention relates to an eye-tracking method and system, more particularly to an eye-tracking method and system that is non-invasive.
2. Description of the Related Art
Eye-tracking technology is typically applied to achieve a hands-free interaction between a user and a computer. In particular, this technology detects movement of the eye of the user, identifies a position of the eye of the user based on the movement of the eye detected thereby, and determines a gazing point corresponding to a gazing location on a screen module which the user is gazing at.
Current eye-tracking technologies are divided into two categories, namely invasive and non-invasive eye-tracking technologies.
In a conventional invasive eye-tracking technology, a contact lens mounted with an inductance coil is worn by the user. The contact lens, however, when worn by the user, irritates the eye of the user.
In another conventional invasive eye-tracking technology, electrodes are attached to a periphery of the eye of the user. The electrodes, however, when attached to the periphery of the eye of the user, causes discomfort to the user.
In a conventional non-invasive eye-tracking technology, the user carries a camera and a light source on his/her head. This, however, causes excessive strain on the user's neck, which may eventually lead to neck injury.
In another conventional non-invasive eye-tracking technology, the camera and the light source are placed on a stationary support, such as a table, in front of the user. However, since the user will inevitably move his/her head toward and away from the camera and the light source while using this technology, the gazing point determined by this technology may be erroneous.
In yet another conventional non-invasive eye-tracking technology, such as that disclosed in U.S. Pat. No. 7,197,165, the eye and the eyebrow of the user are first identified from a pre-captured 3D image of the head of the user, and then the eye and the eyebrow are converted into a 2D image from which a position of the eye of the user is identified. This technology, however, incurs high software and hardware implementation costs.
Furthermore, the accuracy of the gazing point determined by the aforementioned conventional technologies is relatively low. In order to solve this problem, a method for correcting the gazing point has been proposed. In this conventional correcting method, four points, each of which corresponds to a position of the eye of the user while the user is gazing at a respective one of four corners of the screen module, are first established, and the gazing point is then interpolated from the pre-established points. Although this conventional method improves the accuracy of the gazing point, greater accuracy is still required for the gazing point.